Interest in the UFO phenomenon has been growing ever since the late forties when stories of strange flying objects accompanying WW2 aircraft's were circulated and particularly after the press picked up on the account by businessman Kenneth Arnold in 1947 of a formation of nine brightly colored crescent shaped crafts seen from his light aircraft as they flew at speeds in excess of 1200 knots. They were described by Mr. Arnold as flying like saucers skipping across water - and this gave birth to the name flying saucer.
As a result of mankind being naturally war-like and afraid of the unknown, and with Hollywood always seeking to produce more dramatic and scary films, soon flying saucers became the subject of doom-laden and mostly poorly made films presenting flying saucers as the vessels of terrifying invaders from space intending to destroy us and devour our natural resources before moving on to their next victims in a nearby solar system. Many of these films have ranked alongside the lower quality productions in the science fiction and horror film genres, resulting today in any attempt at serious discussion about UFOs and extra-terrestrial life being met with giggles and mockery. So any serious research and scientific study of the UFO phenomena has been very limited in scope.
It is perhaps ironic that millions of dollars of private money and a NASA grant given to S.E.T.I (Search for Extraterrestrial Intelligence) results in a search of deep space for signs of intelligent life, while all the time a large piece of the ET jigsaw appears to be silently going about its business right under our noses here on Earth. S.E.T.I, perhaps understandably, distances itself from the UFO phenomena, preferring to ignore the hundreds of credible sightings of strange crafts by sane and professional people. This denial of the UFO phenomenon reminds the writer of a Christmas pantomime where the lead character is shouting "what?" and "where?" and the audience is shouting "behind you!”
What are the chances that some of these intelligent life forms have visited us and continue to do so? Firstly, a bit of humility is required. Essentially, when it comes to the universe, its origins, its future, life-starting conditions, alternative life-starting conditions, extra-terrestrial life, and advanced ET technology, then let us be honest with ourselves, we know next to nothing. We have only come along very recently in the life of our planet and our scientific discoveries and developments have only really taken place during the last 300 years or so. What can we know of the technology and abilities of ET civilizations that have won the ability to develop scientifically over periods of thousands or even millions of years?
Even if the speed of light is in fact the cosmic speed limit policed by the laws of physics then it is perhaps worth considering that it is not the distance that is the problem, it is actually the time taken to travel the distance. Here on Earth we relate everything back to our own time references and to our human life span. More advanced civilizations might have resolved the problem of aging, and perhaps even death itself. Their life span may extend into many hundreds of years as a result of their understanding of their own physiology and their environment. Their planet may be as large as our sun and rotate slowly with one of their days being equivalent to hundreds of ours. So their perception of time will be entirely different from our own.
Consequently a trip of say 30 of our years may well be a snip to them because their perception of time and time references are entirely different from ours. Add a bit of hibernation and a little on-board entertainment and they will be exploring our solar system in no time, to them, at all. This time reference theory does not even take into account the possibility of tricks with the space-time continuum, faster-than-light travel or inter-dimensional travel that we are many years away from comprehending.
The upshot of the above points is that we are in no position technologically to discount anything when it comes to the universe, space travel and the capabilities of life forms beyond Earth. We should have a little humility considering our embryonic sciences and keep our minds open when it comes to reported UFO sightings.